Armored conductor



Nov. 25, 1930. J. E. 'MCAULIFFE 1,732,787

7 ARMORED GONDUCTOR Filed May 1. 192a ATTORN EY Patented Nov. 25, 1930UNITED STATES PATENT OFFICE,

JOHN E. mcAULIEEn oE BROOKLYN, NEW-YORK, ASSIGNOR 'ro TRIANGLE coNnUrrcoMrANY, or BROOKLYN, NEw YORK, A CORPORATION on NEW YORK ARMOREDCONDUCTOR Application filed May 1,

. This invention relates to armored conductors but more specifically toan insulated conductor enclosed in a spirally wound metal armor.

The object of the invention is to provide in an armored cable of thetype above set forth an electric conductor located between theinsulation and the metal armor and contacting -with the convolutions ofthe armor so that said conductor functions to carry the current andbridge any gaps in the convolutions of the armor, should the conductorsbe short circuited through the armor for any reason.

In the present type of armored cable, if one of its conductors isgrounded on the armor and the armor is compelled to carry the current,it may heat to such a point that a fire hazard is the result. If thearmor is perfectly made so that metal contact is had throughout allpoints of contact of the con-- volutions, an electric current will passlongitudinall through the armor and blow a fuse before there can be anyfire hazard. If, on the other hand, the armor be imperfectly made orimperfectly installed or injured in any way, there is a possibility of agap or gaps between the convolutions of the armor and 1n such an eventthe current will follow the spiral path of the metal forming the armor,$0 that a resistance will be provided to generate heat and constitute afire hazard.

It is therefore thebroad purpose of my invention to provide-what maybetermed a safety device, located within the armor, and constituting anelectric carrier which will compel the current to travel longitudinallyof the armor in the event of short circuiting and which will bridge anygaps whichmay exist between the convolutions of the armor.

This safety conductor need not be of the fullcurrent carrying capacityof the cable as it is to be understood that the armor itself will carrythe major portion of the current and the safety conductor is only toinsure a bridging of any gaps which may exist between the convolutionsof the armor.

- With these and other objects in view, the

- invention consists in certain novel features of construction andcombinations and arrangements of parts, which will be more fully 1928.Serial No. 274,343.

an ordinary wire or maybe any suitable current carrying device whichextends lon tudinally of the armor and is in contact with the innerfaces of all the armor.

This conductor 4 has no function except. when for some reason or otherthe current enters thearmor, as, for example, when the insulation is bador burned out or injured for some reason and there is a short circuit orground through the armor. In such an event the electric conductor 4, orsafety device as I term the same, contacts with all the convolutions ofthe armor and compels the current to travel longitudinally of the armor,the armor itself functioning also as a current carrier and preventingany possibility of the electric current following the convolutions ofthe armor.

The electric conductor 4 need not be of the full current carryingcapacity, although it might be if desired, but the function of thisconductor is to compel the current to flow longitudinally of the armor,and the conductor may be slightly embedded in the insulation, as shownin Figure 2.

It is of course needless for me to explain in detail the manyadaptations of this device in connection with difierent types of fuse,but it is a fact that the current will in any event of short circuitingor grounding flow through the metal of the armor for a certain length oftime before a fuse is blown; and to compel the current to flowlongitudinally of the armor and not follow the convolutions 0f theconvolutions of thereof is the broad idea of my invention which I desireto cover by a patent.

I therefore do not wish to be limited to specific details ofconstruction and combinations and arrangements of parts but-desire tocover the idea broadly as more fully hereinafter expressed in theappended claims.

I claim:

1. The combination with an insulated conductor and a spirally woundmetal armor around the insulation of the conductor composed ofinterlocking turns, of a safety conductor constituting an electricbridge located inside of the armor,insulated from the firstmentionedconductor, and contacting with substantially all of the turns of thearmor, said armor tightly embracing said insulated conductor and saidsafety conductor.

2. The combination with an insulated conductor and a safety conductor,of a spirally wound metal armor composed of interlocking turns enclosingsaid insulated conductor and said safety conductor under pressure,

said safety conductor contacting with substantially all of the turns ofsaid armor to constitute an electric bridge.

3. In an armored electric cable the combination with a plurality ofinsulated electric conductors and a bare electric bond 'wire disposed inlongitudinal relation, of a spirally wound metal armor ofinterlocking-turns tightly embracing said conductors and bond wire sothat the bond wire is partially impressed in said insulated conductorsand held in contact with the turns of the armor.

Signed at Brooklyn, N. Y., in the county of Kings and State of New York,this 26th day of April, 1928.

